iOS7以下 window add view 转屏问题

[[UIApplicationsharedApplication].delegate.windowaddSubview:view];

当使用上述代码加view时候，转屏，view不会自动转，解决方案如下：

UIWindow* window = [UIApplicationsharedApplication].keyWindow;

    if (!window)

        window = [[UIApplicationsharedApplication].windowsobjectAtIndex:0];

    [[[windowsubviews]objectAtIndex:0]addSubview:view];